Feeding mechanism for sewing machines



1936 I N. KNAUS limit FEEDING MECHANISM FOR SEWING MACHINES Filed June 20, 1935 l '2 ShetS-Sheet 1 Aug. 25, 1936. N. KNAUS IEEEDING MECHANISM FOR SEW ING MACHINES 2 Sheets-Sheet 2 Filed June 20, 1955 Patented Aug. 25, 1936 MACHINES Nicholaus Knaus, Newark, N. J., assignor to The Singer Manufacturing Company,

Elizabeth,

N. J., a corporation of New Jersey Application June 20, 1935, Serial No. 27,512

1 Claim.

This invention relates to improvements in sewing machines, and more particularly to an adjusting mechanism for differential or gathering feeding mechanism embodying two feed-dogs which are given differential movements relative to each other.

The several features of the present invention will be clearly understood from the following description and accompanying drawings in which:-

Figure 1 is a top plan view, partly in section, showing my improved feed-adjusting mechanism embodied therein.

Figure 2 is a sectional view taken substantially 1- along the line 2-2 of Figure 1.

Figure 3 is a rear elevation of a portion of a sewing machine showing my improved adjusting mechanism applied thereto.

Figure 4 is a perspective view of the feedadjusting mechanism.

Figure 5 is a disassembled perspective view of the feed-adjusting mechanism.

As illustrated in the drawings, my improved feed-adjusting mechanism is shown applied to an overseaming machine such as that disclosed in the patent to A. Grieb, No. 933,033, dated Aug. 31, 1909. In the embodimentshown, l is the bed of the machine having suitable bearings in which are journaled a main-shaft 2, and rearwardly extending bearing supports 3 formed with suitable bearing apertures to receive the feedrock shaft 4.

Fixed upon the feed-rock-shaft 4 is the feedrocker 5 having two spaced lateral arms 6 and "I, each arm having an apertured end which receives a pivot-pin 8. The feed-rocker 5 receives an oscillatory movement from the main-shaft by means of a pitman 9 having one of its ends embracing an adjustable eccentric I0 on the mainshaft 2, and its other end connected by a pivotpin H to the depending arm l2 which has its split-hub l3 secured to the feed-rocker 5.

Disposed intermediate the arms 6 and I of the feed-rocker and carried by the pivot-pin 8 is the enlarged apertured end 14 of the auxiliary feedbar l5 which carries on its forwardly projecting end It the auxiliary feed-dog IT. A main feedbar I8 is slidably carried on the auxiliary feedbar 15, the main feed-bar being provided with a rib l9 which enters the channel 20 in the auxiliary feed-bar and a longitudinal aperture 2| which receives the stud 22 carried by the auxiliary feed-bar. The above described connection permits the main feed-bar to be reciprocated on the auxiliary feed-bar and independently thereof,

but connected thereto, so as to be moved up and down therewith. The forward end of the main feed-bar carries a main feed-dog 23 which is located in rear of and substantially in alignment with the auxiliary feed-dog ll. 5

The auxiliary feed-bar l5 overhangs the usual feed-lift eccentric 24 on the main shaft and a short pitman 25 embracing the feed-lift eccentric is pivotally connected to the bar 15 by means of a pivot stud 26 carried by the pitman. 10. Through this connection with the main shaft, the feed-bars receive their rising and falling movement. The above described differential feeding mechanism is substantially the same as that forming the subject of my Patent No. 1,959,- 15 719, dated May 22, 1934, to which reference may be had for a more detailed description.

To vary the throw of the main f eed-dog relative to the auxiliary feed-dog the main feed-bar i8 is connected by the link 21 to the bell-crank lever 20 28 which is pivotally secured to the rocker-arm l by the pivot-stud 29. The lever 28 is formed with a rearwardly projecting thumb-piece 30 and a locking lever 3! is pivotally secured to the member 28 by the pivot-stud 32. A spring 33 25 having one of its ends reacting against the end of the thumb-piece 30 and its other end reacting against the locking lever urges the locking lever in a counterclockwise direction, as viewed in Figure 2. A plate 34 is clamped between the 30 rocker-arm l and the lever 28 by the screw 29 and a portion of the plate is notched to receive the feed-rocker 5 to hold the plate against turning movement relative to the feed-rocker (Fig. 5).

The plate 34 is formed with teeth 35 with which 35 the teeth 365 of the locking lever 3| cooperate to hold the bell-crank lever 28 in its various operative positions. From the above it will be .obvious that by pressing the thumb-piece and the locking lever together, the teeth 36 of the locking 40 lever are disengaged from the teeth 35 of the plate 3d and the bell-crank lever 28 may then be swung about its fulcrum to adjust the end of the lever 28, to which the connecting link 21 is secured, nearer to or farther from the pivotal 5 axis of the feed-rocker, thereby decreasing or increasing the feeding movement transmitted to the auxiliary feed-bar.

To indicate the amount of feeding movement given to the main feed-bar, in any adjustment 50 Having thus set forth the nature of the invention, what I claim herein is:

Feeding mechanism for sewing machines including, a pivoted feed-rocker formed with laterally extending arms, mechanism for vibrating said feed-rocker about its pivot, a feed-bar having one of its ends pivoted to said feed-rocker, a second feed-bar carried by said first mentioned feed-bar for horizontal sliding movement relative to said first mentioned feed-bar, mechanism for raising and lowering said feed-bars in unison,

a link having one of its ends pivoted to one end 0! said second mentioned feed-bar, a member pivotally carried by one of the arms of said feed-rocker and pivotally connected to the other end of said link, and means for moving said member about its pivotal connection on the rocker-arm to bring the pivotal connection between said member and said link closer to or further away from the pivotal axis of said feed-rocker. 

